1. Field of the Invention
The present invention relates to an automotive bucket seat, and in particular to a seat back of such automotive bucket seat.
2. Description of Prior Art
In general, an automotive bucket seat is of a relatively deep seating configuration to receive a seat occupant therein in an embracing way. Namely, the configuration of such bucket seat features a deeply recessed formation of its seat back, and the seat back per se is formed to have a main seating portion and a pair of forwardly protrudent side support portions. In particular, the waist and shoulder support regions of each of the two side support portions project more forwardly than the main seating portion to provide an improved embracing support touch to the seat occupant.
Some of the bucket seats of this kind have a divided seat back structure comprising upper and lower seat back portions, as disclosed from the Japanese Laid-Open U.M. Publication No. 63-118854. According thereto, a vertical adjustment mechanism is provided between the upper and lower seat back portions so as to enable vertical adjustment of the upper seat back portion with respect to the lower seat back portion to thereby provide an optimum back support area to a different physique of each different seat occupant.
However, in such conventional seat, all the upper and lower seat back portions are provided with a same foam padding of same hardness or density therein, and further, hard portions of the vertical adjustment mechanism and/or seat back frame connection portions are exposed adjacent to both sides of the seat occupant. As a consequence thereof, it is difficult to adjust a uniform embracing support touch to both of the upper and seat back portions. In particular, when applying a structural modification to the upper seat back portion to improve support touch to the head and shoulder portions of the seat occupant, it is quite difficult to structurally modify the lower seat back portion in order to attain a proper embracing support touch to the waist portion of the seat occupant accordingly. The exposed hard portions, such as a portion of the vertical adjustment mechanism or the seat back frame connection portions, gives an unpleasant hard touch to the lateral body portions of the seat occupant.
Moreover, in this kind of bucket seat, during a long period of time for his or her being seated therein, the seat occupant gets to feel hot and stuffy at the back portion and become uncomfortable in the seat. The same goes especially for the case where a heater is built in the seat back of the seat.